RXTE was used for sustained long-term X-ray monitoring of sources
-- over 5-10 years in many cases. RXTE's two co-aligned instruments,
the Proportional Counter Array (PCA; 2-60 keV) and the High-Energy
X-ray Timing Experiment (HEXTE; 15-250 keV), provided simultaneous
broadband X-ray coverage from 2 to >100 keV for the brightest AGN.

For each object, we provide 2-10 keV ASCII-format flux light
curves from PCA data, with one point per observation. For objects
with sufficient flux, we also include light curves for the sub-bands
2-4, 4-7 and 7-10 keV. For selected bright blazars, we include light curves
of photon index Γ, obtained from model fits to 3-15 keV PCA
spectra while accounting for absorption by the Galactic column.

Data reduction details:
PCA spectra were extracted for each observation using HEASOFT version 6.7 and
the "rex" perl script. We extracted PCA STANDARD-2 data from PCUs 0,
1 and 2 prior to 1998 December 23; PCUs 0 and 2 from 1998 December 23
until 2000 May 12; and PCU 2 only after 2000 May 12. We used only events
from the top Xe layer in order to maximize signal-to-noise. Standard
screening was applied: data were rejected if taken with 20 minutes of
the spacecraft's passing through the South Atlantic Anomaly
(TIME_SINCE_SAA), if ELECTRON0 > 0.1 (ELECTRON2 for data after 2000
May 12), if the spacecraft was pointed within 10 degrees of the Earth,
or if the source was > 0.02 degrees from the optical axis. All
time-averaged spectral files were using the 2011 PCA background models
"pca_bkgd_cmvle_eMv20111129.mdl" or
"pca_bkgd_cmfaintl7_eMv20111129.mdl" for source fluxes
brighter/fainter than ∼5 mCrab, respectively.
HEXTE Science Event data used the same screening criteria as for the PCA.

The PCA response evolved gradually during the mission due to gas
exchange between the propane layer and top-most Xenon layer. PCA
responses were thus generated for each observation separately using
PCARSP version 11.7.1. For the summed spectrum, the individual PCA
responses were summed with weighting according to good exposure time.
The PCA response file available for download for a given object is
thus appropriate for that object only.

Light curves are in units of flux, with one data point per observation:
fluxes/photon indices were obtained by spectral fitting for each observation.
For the 2-10 keV light curves, we applied the best-fit time-averaged spectral model to each individual observation
(exceptions: we fit a broken power-law model to the time-averaged spectra of
1ES 1101−232 and Mkn 501, but an unbroken power law provided good fits to their individual spectra).
The spectral parameters that we kept free and the bandpass that we used are listed in the header of
the 2-10 keV ASCII light curve.
We usually kept photon index, power-law normalization, and the intensity of the Fe Kα emission line
(if present in the time-averaged spectrum) free,
while keeping all other parameters such as those for
Compton reflection components or absorption components, or energy centroid and width
of the Fe Kα line frozen at
their time-averaged values unless otherwise stated.
We fit over the bandpass 3.3 keV to 10, 18, or 23 keV, depending on the source's
average X-ray brightness (2-10 keV flux typically >∼ 7×10−11,
∼1.5 −∼7×10−11, and <∼1.5×10−11
erg cm−2 s−1, respectively, with flux boundaries ∼a third lower
for heavily-absorbed type 2 sources).
Sub-band light curves were generated via a simple power-law to that
band only; we used the 2005 background files, and will reprocess them
using the 2011 background models at some point in the future.
Uncertainties on each flux point were obtained by
dividing the standard deviation of the N 16-s binned count rate
light curve points in that observation by sqrt(N). Uncertainties on
photon index are at the 90% confidence level, corresponding to Δχ2=2.71.
For three bright sources, we added systematics to obtain values of
reduced χ2 near 1: 3%, 5% and 5% for NGC 5506, NGC 4151
and Cen A, respectively. Entries in the time column correspond to the mid-point of each
observation after data screening.

The following sources were modeled by Rivers et al. (2013) with ionized absorption: IRAS 13349+2438, Mkn 766, NGC 3227, NGC 3516, NGC 3783, NGC 4051, NGC 4593, NGC 5548, PG 0804+761. For those sources, we include an XSTAR table as part of the spectral files available for download.

2. Spectral fit systematic uncertainties:
The listed uncertainties on model fit parameters are purely statistical.
Systematic uncertainty associated due to unmodeled variations in the
PCA or HEXTE X-ray background will present an additional contribution
to the uncertainties on parameters for broad components (e.g.,
power-law photon index Γ), with the exact amount depending on
the bandpass used. For example, consider the case of a relatively
faint source with a PCA-only spectrum modeled by a simple power law
over the 2-20 keV band. For a 2-10 keV flux of ∼9 ×
10−12 erg cm−2 s−1,
one might expect additional systematic uncertainty on Γ of
∼0.10-0.15. For a 2-10 keV flux of ∼6 ×
10−12, additional uncertainty on Γ can be
∼0.15-0.25.

4. HEXTE Considerations: Cluster Rocking, Evolution in
Background: HEXTE consisted of two clusters, A and B, both of which gathered
simultaneous background data by two-sided rocking to offset positions
every 16 or 32 s. We do not combine Cluster A and B data. Detector 2 in
Cluster B lost spectral capabilities in 1996 and we consider data from
detectors 0, 1, and 3 only.

Cluster A did not rock on/off source during
2004 Dec 13 - 2005 Jan 14, 2005 Dec 12 - 2006 Jan 4, during
2006 Jan 25, and it stopped rocking permanently on 2006 Mar 14.
Cluster B stopped rocking on 2009 Dec 14. (Please see the
"RXTE Big Events" web page for additional details.)
We do not consider data taken after these dates.
Good exposure times for the summed HEXTE spectra
will differ significantly between Cluster A and Cluster B
if a given source was observed during 2006-2009.

As a very rough guideline for analyzing
binned HEXTE spectra: When the 20-100 keV net source flux is
less than ∼7×10−11 erg
cm−2 s−1, the highest useable energy
bin will be (very roughly) ∼ 120-150 keV, 80-100 keV, or 50 keV
typically when the exposure time for one cluster is >∼250 ks,
∼50-250 ks, or <∼50 ks, respectively. The highest useable
energy bin can be ∼150-240 keV only when the 20-100 keV flux is
above ∼7×10−11 erg cm−2
s−1, and/or if the good exposure time per cluster
HEXTE is above a couple hundred ks.

HEXTE exposure times have been corrected for dead-time (typically
30-40%) due to cluster rocking, pulse analyzer electronics, and
recovery time following scintillation pulses caused by high energy
particles. Exposure times for the summed spectra are typically less
than half that of the summed PCA spectrum for a given object.

The summed HEXTE spectra for each of the 23 sources in Rivers et
al. (2011) are detected at 3σ or better out to 100 keV; these
sources have F20-100 greater than
∼5-8×10−11 erg cm−2
s−1.

How to acknowledge use of this catalog:
If you publish any data obtained from this web site, we would like you to include
the following acknowledgment: "This work has made use of {lightcurves}{spectral files}
provided by the University of California, San Diego
Center for Astrophysics and Space Sciences, X-ray Group
(R.E. Rothschild, A.G. Markowitz, E.S. Rivers, and B.A. McKim),
obtained at http://cass.ucsd.edu/∼rxteagn/."
Secondly, please also cite Rivers, Markowitz, & Rothschild (2013), ApJ, 772, 114.
Finally, please send us an email (almarkowitz, rrothschild
-at- ucsd -dot- edu) to let us know what you're doing; if you are
doing an in-depth analysis and/or using multiple sources,
we may like to discuss possible co-authorship. Thanks!

In the future, we will add
7-10/2-4 hardness ratio plots, as well as
10-18 keV PCA light curves and
HEXTE light curves for selected bright sources.